Stethoscopic device



2 Sheets-Sheet 1 Filed Nov. 16. 1960 April 23, 1963 .1:13. DAHL 3,087,016

STETHOSCOPIC DEVICE Filed Nov, 16. 1960 '2 Sheets-Sheet 2 United States Patent O 3,087,016 STETHOSCOPIC DEVICE Joseph D. Dahl, Minneapolis, Minn. Filed Nov. 16, 1960, Ser. No. 69,734 11 Claims. (Cl. 179-1) This invention relates to an improved construction of a stethoscope, and more particularly to a construction comprising a combination of an air -bell type 'and electronic stethoscope. In an 1air bell type of stethoscope there is a direct contact of the device to the chest wall of the patient and the sound is transferred through a closed air system by way of using binaurals to the ears `of the operator. A standing pressure wave exists within this closed system at all times. The coupling of the heart to the chest wall of the patient yforms an acoustical impedance path. The air coupling of the air bell pickup to the ears of the operator is of -high impedance. Thus there is here formed a severe mismatch of sound quality, -and this mismatched quality is the sound heard by the operator and is one which he has learned to interpret traditionally into specic pieces of information.

In a conventional design of Ian electronic type of stethoscope the closed air system does not exist and there is obtained a sound pattern altogether dissimilar from that resulting from the use of an .air bell type of stethoscope. The operator therefore has to become especially trained in order to interpret the sounds heard electronically as they are not related in character to the sound of an air bell pickup type of stethoscope.

It is desirable therefore `to have a stethoscope providing the traditionally understood sound of an lair bell type of stethoscope and to include within the same instrument means for providing an electronically amplied sound having similar characteristics whereby one sound is easily related -to the other with the electronically produced sound having greater amplification 'and providing more complete .sound pickup.

It is an `object of this invention therefore to provide in a single instrument a combination of an air bell type and an electronically operated stethoscope.

rlt is a further object of this invention to provide in a single stethoscope a direct interchange between air and electronic operation with each `operation producing sounds having similar characteristics.

It is another 4object of this invention to provide a stethoscope comprising an integral unit easily held in the hand of an operator having a switch in a position to be normally engaged yby a portion of the operators hand for a quick conversion of said stethoscope to either an air or an electronic operation.

-lt is also an object of this invention to provide a stethosco-pe comprising a switch for closing the air operation and actuating the electronic operation of the same, and also providing in the electronic operation a tone control for selecting certain frequency ranges for the reception of certain specic body sounds.

It is a further object of this invention to provide in connection with the -above mentioned object means which may be operated as by the thum'b of the operator, with said means being normally in position to provide for the air operation of said steth-oscope, and constructed to be depressed to close off the air oper-ation and actuate the electronic operation of the stethoscope, and further to be rotatable by movement of the thumb with the stethoscope in operating position for the selection of a specific frequency range for the reception of certain ybody sounds.

More specifically it is an object of this invention to provide in combination an air bell type and an electronically operated stethoscope operating in either case as a closed system with no communication with the outside 3,087,016 Patented Apr. 23, 1963 atmosphere as `from the chest wall of the patient to the ears `of the operator with means for interchanging during operation `from an air operation to an electronic operation with the sounds being produced by either operation having similar identifiable characteristics.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in which like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 is a view in rear elevation of applicants device with a portion broken away;

FIG. 2 is a View `on an enlarged scale in vertical section taken on line 2-2 of FIG. l as indicated by the arrows;

FIG. 3 is a fragmentary view -of applicants device showing a portion thereof on an enlarged scale in vertical section in one operating position;

FIG. 4 is a top plan view of a portion of applicants device shown on an enlarged scale; and

FIG. 5 shows a wiring system for applicants device, generally of a conventional form.

Referring to the drawings, applicants -device 10 is `shown in combination as an air bell and electronic stethoscope. Used in connection with `applicants device is the binaural ear attachment 13 of conventional design having ear tip portions 12 and a coupling hose 14 having its terminal portion 14a friction-ally disposed onto the projecting sound conveying tube 17a carried by the end cap 17.

Applicants device may take various specific forms. It is here shown comprising a handle portion 15 having a cylindrical body casing or housing 16 having said end cap 17 secured thereon as by being threaded onto the lower end portion thereof and having an end cap 18 secured onto its upper end as by being frictionally pressed thereon. Said housing 16 is indicated in FIG. 2 as having an upper chamber 16a and an offset lower chamber 16b being somewhat lesser in diameter forming a shoulder 16C thereabout.

Said upper cap 18 has an aperture 18a centrally thereof through its closed end portion and through lwhich is disposed a short bolt 20 having `a longitudinal bore 20a forming a passage therethrough.

Constructed and arranged to be secured to said end cap 18 by said bolt 20 is a head portion 25 comprising an open-ended housing 27 substantially frusto-conical in form. Said housing 27 is formed to have a plate portion 27a forming a transversely disposed wall substantially centrally thereof forming open-ended chambers 28 and 29 at either side thereof with said chamber 28 here being shown to be somewhat larger in diameter than said chamber 29, and with said chamber 29 being somewhat greater in depth. Disposed in said chamber 28 is a cylindrical magnetic sound pickup head 31 of conventional design being secured in position by a screw 32 disposed through said plate 27a. Said pickup head is spaced somewhat from the bottom of said 4chamber 28 by a slightly extended hub portion 31a of said pickup head to yform an air passage thereunder for communication 4between said chamber 28 and said chamber 29 through the rai-r passage of air vent 34 extending centrally through said plate nortiOn 27a.

Secured in said chamber 28 adjacent said pickup head is a conventional input capacitor 36. Adapted to overlie `said chamber 28 to rest on the rim portion thereof cushioned by a gasket 37 is a metallic diaphragm 38 of a common type held in position by an annular collar 3-9 having a rim portion 39a overlying the periphery of said diaphragm 38 and having a wall portion 39h frictionally engaging the offset outer end portion 27a of said housing 27. Said collar 39 is pressed into holding position L to be frictionally held in position on said housing 27. A small aperture 27C is shown through the plate 27a for the passage of electrical wires and said passage will be air sealed in a suitable manner.

Said chamber 29 is shown having an offset internally threaded outer portion 29a of somewhat larger diameter `and having a shoulder 29h formed therebetween. Supported on said shoulder is a resilient ring 41, as of sponge rubber, being of sufficient thickness to allow some movement inwardly of said chamber as by compression thereof, as will hereinafter be indicated.

Disposed in said outer chamber 29a` is a conventional type of a tone control member 43 comprising a tone wheel 44 and having leads 44a, 44b and 44C extending inwardly of said chamber whereby rotation of said wheel relative to said leads will tune in specific frequency ranges, as will be hereinafter described. Said tone control memlber is mounted on a non-conductive mounting disk 46 which is supported on said resilient ring 41. Said leads 44a, 44b and 44e extend through said mounting disk and are held stationary thereby. Said disk is secured to said tone control member by studs 49, and also secured to ysaid studs and extending inwardly of said chamber 29 is a combination circuit closure switch and air control Valve 51 shown here to be substantially cylindrical in form and adapted to be moved inwardly of said chamber 29 by pressure against the tone control wheel 44 to close the air vent 34 and make electrical contact with the electrical system of applicants device by contact with said plate portion 27a. Threaded into said chamber 29a is a lock ring 52 which will `bear against said disk 46 sumciently to hold the disk in position.

Present on said housing 27 substantially about said tone wheel 44, as indicated in FIG. 4, is indicia 54 showing specific frequency ranges for hearing different body sounds. A range is provided for heart sounds. A range is provided for respiration sounds, and a full range area is provided for body sounds generally. Each range is separated by reference lines 55. In -connection with said reference lines is the reference point 44d on said tone control wheel. Body sounds such as here indicated can be distinguished from one another as they respectively are found within distinct frequency ranges.

Angled into said housing 27, as indicated in FIG. 3, is a tapped bore 2713 for receiving said bolt 20 for securing said handle portion to said head portion 25. It is seen in said FIG. 3 that said cap 118 bears against an edge portion of said lock ring 52 to hold said lock ring from rotation in operating position.

Disposed in said housing 15 at the upper end -thereof is a conventional type of transistorized amplifier package or unit 58 in circuit with said tone control member 43, said pickup head 31 and said input capacitor 36. Said amplifier unit has in circuit therewith a conventional output transducer or speaker unit 59 having contact with a suitable battery 60 held in operating position by a helical spring 61, which spring grounds said battery to the end cap 17. As indicated in FIG. 2, the transducer will be held free of the shoulder 16e and air will pass freely through the housing 15.

With reference to the wiring diagram in FIG. 5, applicants `device comprises a system grounded to the housing of the device. The sound pickup 31 is grounded to the plate portion 27a `and is in circuit with the input capacitor 36 and with the tone control 34 which is in circuit with the transistorized or electronic amplifier 58 of conventional design which is connected to the `output transducer 59 and to the battery 60 for a power source. The diagram indicates conventional wiring and also indicates the wiring of said amplifier 58.

In operation, applicants device is used in connection with a conventional design of a binaural ear attachment 13. The device itself is of such design as to be conveniently held in hand with the thumb 70 of the operator normally resting on the tone control wheel 44 which has integral therewith the circuit closing switch and air seal 51. The diaphragm of the device will be placed `as against the chest wall of the patient, and the |binaural ear attachment used in connection with applicants device will be in position hooked up to the ears of the operator.

In its normal operation applicants device operates as an air lbell type of stethoscope. The stethoscope with its Abinaural ear attachment and coupling hose forms a closed system from the inner face of the diaphragm 38 to the ears of the operator and a standing pressure wave exists between this system at all times. In its use as an air bell type of stethoscope, there is in the applicants device a direct passage of sound from the pickup head 31 through the air passage 34 and through the remaining housing of applicants device directly to and through the coupling hose to the binaural. Thus there is present here the conventional operation of an air bell type of stethoscope.

To change to an electronically operated stethoscope, the operator has only to depress the tone wheel 44 with his thumb and this moves the switch 51 inwardly against the pressure of the ring 41 to contact the plate portion 27a to seal off the air passage 34 and close the electronic circuitry to activate the same. There is thus a complete acoustical seal within the housing of the device with no communication being present to the atmosphere. This prevents any spurious oscillation. Thus there is provided a closed system `for the electronic operation of applicants device and for the electronic pickup and amplilication of the patients body sounds. Said pickup and the electronic amplifier and output transducer operate within an acoustically sealed area to produce sounds having characteristics similar to those produced mechanically by the air bell system. The electifonically produced sounds are readily identifiable with corresponding mechanically produced sounds. Thus a particular heart sound whether produced mechanically or electronically will have similar characteristics and be readily identifiable by the operator in either case. It is the reproduction of sound with an acoustically sealed area which causes the electronic reproduction to be similar to the mechanical reproduction of sound.

The electronic sound pickup picks up a greater range of sounds than does the mechanical operation of applicants device due to the greater sensitivity of the electronic sound pickup whereby the operator has a greater range of sound for use for purposes of study or examination. Further the tone control wheel 44 may be readily rotated by the thumb of the operator for selective sound reception, such as high frequency reception for respiration, low Vfrequency reception for heart sounds, or as here indicated a full range of reception for body sounds generally.

Instant interchange between mechanically and electronically produced sounds may be had for comparison of one to the other as may be desired by the operator.

The operator in one instrument has the benefit of either an air bell |type of 'stethoscope or an electronic stethoscope with tone control or the interchange of one with the other in any study or examination being conducted without the need tfor removing the instrument from any given position on a patients body.

'[lhe device there indicated operated by a small nine volt battery for use with transistors and [battery replacement is simply laccomplished by removal of the lower end cap. The remaining portions of the device are relatively free from need for replacement.

Thus `it `is seen that I have provided a compact and simply operated combination air ibell zand electronic stethoscope With tone control `in the electronic operation and instant interchange between the mechanical and electronic operation thereof. The applicants device represents a .substantial advance in the art.

It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention which, generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

l. A binaural stethoscopic device i `aving in combination, means `for the mechanical operation of said device for detecting and reproducing sound, means tfor the electronic operation of said device tor detecting and reproducing sound, means for the electronic operation oct said device to provide sound having characteristics similar to said mechanically reproduced sound, and means for instant interchange between said mechanical and electronic operation of said device Without moving said device from an operating position and by the hand of the operator holding said device.

2. The structure set rforth in claim l, said last mentioned means hav-ing integral therewith a :tone control member flor the select-ion of certain frequency ranges of sound lreproduction.

3. The structure set forth in claim l, Isaid last menl tioned means comprising a member movable .inwardly for shutting off said mechanical operation vand activating said electronic operation and movable rotatably for the selection of certa-in frequency ranges -f-or tone control.

4. A stethoscopic device in connection with a binaural ear attachment and a coupling hose having in combination, a head portion having a chamber therein, a diaphragm at one side of said chamber, a hand holding body portion having a chamber therein, means for the passage oi air between said chambers and said seco-nd chamber having air communication with said coupling hose and binaural ear attachment, means for sealing said chambers from the atmosphere when said device is in operating position, a magnetic sound pickup in said first chamber, an electronic sound amplifier Iand sound reproducer in said second chamber in operative connection with said pickup for electronic sou-nd pickup and reproduction, and means yfor sealing said -rst chamber from said second chamber .and activating said electronic sound reproduction.

5. The structure set forth in claim 4, said last mentioned means comprising a member carried by said head portion and constructed .and arranged to be engaged by the Ithumb of the operator to be depressed to close oi said means tor passage `of air .and activate lsaid electronic sound reproduction and said member having integral therewith a rotatable tone control mean-s to select a certain frequency range of sound reproduction by rotation thereof by said thumb ci said operator.

6r. A -stethoscopic device in connection with la binaural ear attachment and coupling hose having in combination, a head portion, a hand holding body portion in operative connection with said head portion, chambers respectively in said head 'and body portions having an air passage therebetween, said chambers being `sealed from the atmosphere having a standing pressure wave therein when Isaid dev-ice is in operating position, a diaphragm in said head port-ion for the mechanical oper-ation of said device for detecting and reproducing sound, a magnetic sound pickup in 4said head portion, `an electronic sound amplifier and a sound reproducer in said body portion in operative association with said sound pickup ifor the electronic operation of said device, a hand engaging means on said head portion for cutting off the passage 4of air between said chamber in said head portion 'and said chamber in said body portion and activating said electronic operation.

7. A stethoscopic device in connection with -a bfmaural ear attachment and a coupling hose having in combination, a head portion, an air chamber in said head portion, a diaphragm forming an outer wall of said chamber, a sound pickup in said chamber, a cylindrical hand holding body portion connected to said head portion, an air chamber extending through said body portion, said air chambers being sealed from communication with the atmcsphere when said device is in operating position, electronic means in said body portion for amplifying and reproducing sound in connection with said pickup iior the electronic operation of said device, means for the passage of lair between said lirst and second air chambers, rotatable means carried by said head portion for control in connection with said electronic operation, and said last mentioned means having integral therewith means for shutting off the passage of air between said iirst and second air chambers and for activating said electronic operation lof said device.

8. A binaural stethoscopic device comprising an integral hand holding unit having a pair of spaced chambers therein sealed `trom communication from the atmosphere when said device is in operating position and having air communicationtherebetween, a mechanical sound pickup in Vone of said chambers yfor the mechanical operation `of said device, `a magnetic sound pickup in said chamber, an electronic sound amplifier and reproducer in said second chamber in operative association with said pickup to energize the same 'for the electronic operation of said device, means `carried by said member operable by the hand of the operator holding said device tor shutting off the passage of air between said iirst and second mentioned chambers and activating said electronic operation for instant interchange between the mechanical and electronic operation of -said device, and having integral therewith in :association with said electronic operation means for selecting certain frequency ranges of sound reproduction.

9. A binaural stethoscopic device having in 'combination, a substantially frusto conical head portion having a chamber therein, a diaphragm forming an outer wall of said chamber fo rthe mechanical detection of sound, a magnetic sound pickup in said chamber, an elongated cylindrical portion in operative association with said head portion whereby said cylindrical portion is adapted to be held in the hand ofthe operator with the operators .thumb in normal position engaging said head portion, said cylindrical portion having an air chamber therethrough, means for the passage of air between said chambers with said chambers being constructed and arranged to be sealed from the atmosphere when said device is in operating position and to have a standing pressure wave therein for conducting and reproducing said mechanically detected sound, an electronic sound amplifier and sound reproducer and a source of power in said cylindrical portion in circuit with said sound pickup for the electronic operation of said device, means carried by said head portion engageable by said thumb of said operator for shutting oif the passage of air between said iirst and second mentioned chambers and activating said electronic operation for interchange between the mechanical and electronic operation of said device, and said means having integral therewith rotatable means operable by said thumb of said operator without a change in position of said thumb for the selection of certain frequency ranges of sound in the electronic operation of said device.

l0. The structure set forth in claim 9, said cylindrical portion having a removable end cap portion for the replacement of the source 0f power therein.

1l. A binaural stethoscopic device having in combination, a substantially frusto conical portion, a chamber in said portion, a diaphragm forming an outer wall of said chamber, a substantially cylindrical hand holding body portion, a chamber through said cylindrical portion, said iirst and second mentioned chambers having a passage therebetween for the passage of air, a sound pickup in said first chamber, an electronic sound amplier and reproducer and a source of power disposed in said second chamber in circuit with said sound pickup for energizing the same, a substantially cylindrical rotatable member mounted on said head portion in circuit with said sound pickup for the selection of certain sound frequency ranges, means in association ywith said member extending inwardly of said head portion therefrom for cutting of the passage of air between said rst and second mentioned chambers, resilient means in connection with said cylindrical member for normally holding the same to permit the passage of air between said rst and second mentioned chambers for the normal mechanical operation of said device, said head and cylindrical portions being constructed and arranged to have said rst and second mentioned chambers sealed from communication with the atmosphere when said `device is in operating position whereby both the mechanical and electronic reproduction of sound is effected in a chamber sealed from the atmosphere whereby both the mechanically and electronically reproduced sounds have similarly identifiable characteristics.

References Cited in the le of this patent UNITED STATES PATENTS 1,658,327 Dodge Feb. 7, 1928 2,058,796 Hogle Oct. 27, 1936 2,142,993 Brown Jan. l0, 1939 2,419,471 Thibos Apr. 22, 1947 

1. A BINAURAL STETHOSCOPIC DEVICE HAVING IN COMBINATION, MEANS FOR THE MECHANICAL OPERATION OF SAID DEVICE FOR DETECTING AND REPRODUCING SOUND, MEANS FOR THE ELECTRONIC OPERATION OF SAID DEVICE FOR DETECTING AND REPRODUCING SOUND, MEANS FOR THE ELECTRONIC OPERATION OF SAID DEVICE TO PROVIDE SOUND HAVING CHARACTERISTICS SIMILAR TO SAID MECHANICALLY REPRODUCED SOUND, AND MEANS FOR INSTANT INTERCHANGE BETWEEN SAID MECHANICAL AND ELECTRONIC OPERATION OF SAID DEVICE WITHOUT MOVING SAID DEVICE FROM AN OPERATING POSITION AND BY THE HAND OF THE OPERATOR HOLDING SAID DEVICE. 